The invention relates generally to apparatus and methods for lifting one or more drum in connection with a drum weighing machine.
Various machines and systems involve the handling of drums, barrels or other types of containers (collectively “drums”). Some examples of such machines and systems are drum filling systems and drum processing systems. In connection with such machines and systems, it is often necessary or desirable to precisely weigh the drum to meet drum content requirements, regulatory compliance or any other reason.
Many drum handling machines and systems require the drum to be lifted off a base, conveyor system or other structure in order to be weighed. In such instances, if the drum is not precisely lifted, the measured weight of the drum may be inaccurate. For example, if the platform upon which the drum rests contacts or drags upon an adjacent structure or part of the system, the measured weight may be affected. For another example, if the drum is on a drum filling machine that includes a drum filling lance extended into the drum and is not lifted precisely (or nearly precisely) vertically, the lance may contact the drum during weighing, causing an inaccurate weight measurement.
In many applications, if the measured weight of the drum is inaccurate (even by a mere fraction), the economic, legal, health and welfare and/or other consequences could be severe. For example, in an operation involving the daily filling of a quantity of one-thousand (1,000 ea.) 55-gallon type drums with a chemical costing $25.00 per pound, an inaccurate weight measurement resulting in mistakenly overfilling each drum by one pound (1 lb) will cause an economic loss of $25,000 per day.
Accordingly, there exists a need for drum lifting apparatus and methods used in connection with the weighing of the drum(s) and having one or more of the following attributes, capabilities or features: precise movement in a vertical plane of a drum lifting platform with little or no movement thereof in any other plane; precise lifting of a drum and its contents weighing up to numerous hundreds of pounds; lifting a drum without movement of the drum from side-to-side or back and forth; preventing a drum lifting platform from dragging on adjacent structure; preventing twisting or rotation of a drum lifting platform during lifting and weighing of the drum; assisting in maintaining the desired positioning of a drum filling lance within the drum during lifting and weighing of the drum on a drum filling machine; assisting in maintaining the centering of a drum lifting platform on a drum handling machine.